The LyseBlue indicator dye added to some of the buffers is Thymophthalein, pH shift from colorless to blue at pH 9.3

Recycling Qiagen Columns

The blue and purple Qiagen columns are identical in formulation. They are interchangeable and can be reused multiple times after treatment with hydrochloric acid, re-equilibration, and wash. Very likely this protocol can be used with other similar columns. Unused columns can be cheaply purchased in bulk from Epoch Biolabs.

The reuse protocol is:

Save the collection tubes and columns after elution of DNA

Fill the column with 700 μl of 1 M HCl

Cap and store in an airtight container for at least 24 hours (less than a month)

Wash the columns and collection tubes in a large beaker of water

Assemble the column and collection tube and wash the column with 700 μl of DI water, discarding the water

Repeat

Fill the column with 700 μl of buffer QBT and spin down, discarding the buffer